Cold storage heat exchanger

ABSTRACT

A cold storage heat exchanger for exchanging heat with air flowing therearound includes a refrigerant passage in which refrigerant flows, and a cold storage container that accommodates therein cold storage materials which exchanges heat with the refrigerant flowing through the refrigerant passage and retains the amount of heat from the refrigerant. The cold storage materials having different melting points are accommodated in the cold storage container.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2012-135042 filed on Jun. 14, 2012, the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a cold storage heat exchanger used for a refrigeration cycle device.

BACKGROUND ART

Conventionally, a refrigeration cycle device is used for an air-conditioning system. An attempt is made to provide limited refrigerated air-conditioning even in a state where this refrigeration cycle device is stopped. For example, in an air-conditioning system for a vehicle, the refrigeration cycle device is driven by an engine for traveling. For this reason, when the engine stops while the vehicle is making a brief stop, the refrigeration cycle device is stopped. An “idle reduction vehicle” which stops its engine while the vehicle is stopped, waiting for a traffic light, for example, in order to improve fuel efficiency increases in number. Such an idle reduction vehicle has an issue that the refrigeration cycle device stops while the vehicle is stopped (while its engine is stopped), so that comfortableness of the vehicle interior is impaired. If the engine is restarted even while the vehicle is stopped to maintain an air-conditioning feeling, there is also an issue that an improvement in fuel efficiency is prevented.

Technologies to resolve these issues are described in Patent Documents 1 to 5. According to Patent Documents 1 to 5, a heat exchanger for vehicle interior has a cold storage function to maintain an air-conditioning feeling even while an engine is stopped. Accordingly, cold energy is stored while a vehicle is traveling, and this cold air is used while the vehicle is stopped.

In Patent Document 1, it is described that a cold storage container, in which a cold storage material is sealed, is disposed on a rear side of a conventional evaporator in an air flow direction. In Patent Documents 2 to 5, it is described that a cold storage container having a small capacity is provided adjacent to a tube which constitutes a refrigerant passage of an evaporator, and that a cold storage material is sealed in this cold storage container.

PRIORE ART DOCUMENTS Patent Documents

-   Patent Document 1: JP-A-2009-188518 -   Patent Document 2: JP-A-2010-91250 -   Patent Document 3: JP-A-2010-112670 -   Patent Document 4: JP-A-2010-149814 -   Patent Document 5: JP-A-2011-12947

An evaporator having a cold storage function described in Patent Documents 2 to 5 accumulates cold air in the cold storage material through solidification of the cold storage material in the cold storage container while a compressor for air conditioning is in operation. While idling is stopped, conversely, a solid cold storage material releases cold air into the air, being melted. Accordingly, a temperature change of blown-out air can be limited to maintain an air-conditioning feeling until the cold storage material is completely melted.

However, in case of use under temperature environment where the cold storage material cannot be solidified while idling is stopped, a sufficient amount of cold air cannot be accumulated. Thus, because cold air cannot be released for a long time, there is an issue that an idle stop time is shortened to maintain an air-conditioning feeling.

SUMMARY OF INVENTION

The present disclosure addresses the above issues. Thus, it is an objective of the present disclosure to provide a cold storage heat exchanger that can maintain a cold storage function in a wide range of air temperature.

To achieve the above-described objective, in one aspect of the present disclosure, a cold storage heat exchanger for exchanging heat with air flowing therearound includes a refrigerant passage in which refrigerant flows, and a cold storage container that accommodates therein cold storage materials which exchanges heat with the refrigerant flowing through the refrigerant passage and retains the amount of heat from the refrigerant. The cold storage materials having different melting points are accommodated in the cold storage container. In the cold storage heat exchanger, the cold storage materials include a cold storage material having a high melting point, and a cold storage material having a low melting point. The cold storage material having a high melting point is disposed on an upstream side of the cold storage material having a low melting point in a flow direction of air.

According to the present disclosure, the cold storage materials having different melting points are divided from each other and accommodated respectively in the cold storage container. The cold storage material having a high melting point is disposed on an upstream side of the cold storage material having a low melting point in a flow direction of air. Accordingly, when the temperature of the refrigerant is, for example, equal to or lower than, the melting point of the high melting point cold storage material, and is equal to or higher than the melting point of the low melting point cold storage material, only the high melting point cold storage material is solidified. As a result, even though the refrigerant temperature is high, the cold storage can be carried out. When the refrigerant temperature becomes further low, all the cold storage materials are solidified. Thus, the cold can be stored in stages in accordance with the refrigerant temperature. Therefore, a cold storage function can be maintained in a wider range of air temperature.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:

FIG. 1 is a front view illustrating an evaporator 40 of a first embodiment;

FIG. 2 is a side view illustrating the evaporator 40 of the first embodiment;

FIG. 3 is an enlarged sectional view illustrating a part of a surface of section taken along a line III-III in FIG. 1;

FIG. 4 is a sectional view illustrating a cold storage container 47 of the first embodiment;

FIG. 5 is a diagram illustrating cold storage states of two cold storage materials 50 a, 50 b in the first embodiment;

FIG. 6 is an enlarged sectional view illustrating a part of section of an evaporator 40A of a second embodiment;

FIG. 7 is a sectional view illustrating a cold storage container 47 of the second embodiment;

FIG. 8 is a sectional view illustrating a cold storage container 47C of a third embodiment;

FIG. 9 is a sectional view illustrating a cold storage container 47D of a fourth embodiment;

FIG. 10 is a sectional view illustrating a cold storage container 47E of a fifth embodiment;

FIG. 11 is a sectional view illustrating a cold storage container 47F of a sixth embodiment;

FIG. 12 is a sectional view illustrating an evaporator 40G of a seventh embodiment;

FIG. 13 is a sectional view illustrating an example of an evaporator 40H of an eighth embodiment;

FIG. 14 is a sectional view illustrating another example of an evaporator 40I of the eighth embodiment;

FIG. 15 is an enlarged sectional view illustrating a part of an evaporator 40 of a ninth embodiment;

FIG. 16 is a sectional view illustrating a cold storage container 47 of the ninth embodiment; and

FIG. 17 is a diagram illustrating cold storage states of two cold storage materials 50 a, 50 b of the ninth embodiment.

EMBODIMENTS FOR CARRYING OUT INVENTION

Embodiments will be described below with reference to the drawings. In the embodiments, for a part corresponding to a matter described in the preceding embodiment, the same reference numeral may be provided or a single numeral may be added to the preceding reference numeral, thereby omitting a repeated explanation. In the embodiments, when a part of configuration is described, the other part of the configuration is similar to the precedingly-described embodiment. As well as a combination of the parts specifically described in the embodiments, a partial combination between the embodiments is possible unless the combination has a particular adverse effect.

First Embodiment

A first embodiment will be described in reference to FIGS. 1 to 5. An evaporator 40 constitutes a refrigeration cycle system (not shown). The refrigeration cycle system is used for, for example, an air-conditioning system for a vehicle. The refrigeration cycle system includes, although not shown, a compressor, a radiator, a decompressor, and the evaporator 40. These components are connected through a pipe annularly to constitute a refrigerant circulation passage. The compressor is driven by a power source for vehicle traveling. Accordingly, when the power source stops, the compressor also stops. The compressor draws in the refrigerant from the evaporator 40, compresses the refrigerant, and discharges the refrigerant into the radiator. The radiator cools high-temperature refrigerant. The radiator is also referred to as a condenser. The decompressor decompresses the refrigerant cooled by the radiator. The decompressor can be provided by a fixed throttle, a temperature type expansion valve, or an ejector. The evaporator 40 evaporates the refrigerant decompressed by the decompressor to cool a medium. The evaporator 40 cools the air supplied to the vehicle interior.

The refrigeration cycle system can further include an internal heat exchange that exchanges heat between high-pressure side liquid refrigerant and low-pressure side gas refrigerant, or a tank element of a receiver or accumulator that stores surplus refrigerant. The power source can be provided by an internal combustion engine or an electric motor.

As illustrated in FIGS. 1 and 2, the evaporator 40 is a cold storage heat exchanger, and includes a refrigerant passage member branching into more than one portion. This refrigerant passage member is provided by a passage member made of metal such as aluminium. The refrigerant passage member is provided by headers 41 to 44 positioned in groups, and refrigerant pipes 45 connecting together these headers 41 to 44.

The first header 41 and the second header 42 are grouped and arranged in parallel with each other with a predetermined distance therebetween. The third header 43 and the fourth header 44 are grouped and arranged in parallel with each other with a predetermined distance therebetween. The refrigerant pipes 45 are arranged at regular intervals between the first header 41 and the second header 42. Each refrigerant pipe 45 communicates with the inside of a corresponding header at its end part. A first heat exchange part 48 is formed by the first header 41, the second header 42, and the refrigerant pipes 45 arranged therebetween. The refrigerant pipes 45 are arranged at regular intervals between the third header 43 and the fourth header 44.

Each refrigerant pipe 45 communicates with the inside of a corresponding header at its end part. A second heat exchange part 49 is formed by the third header 43, the fourth header 44, and the refrigerant pipes 45 arranged therebetween. As a result, the evaporator 40 includes the first heat exchange part 48 and the second heat exchange part 49 which are arranged with two tiers. In an air flow direction, the second heat exchange part 49 is disposed on an upstream side, and the first heat exchange part 48 is disposed on a downstream side.

A joint (not shown) as a refrigerant inlet is provided at an end part of the first header 41. The inside of the first header 41 is divided between a first section and a second section with a partition plate (not shown) provided at nearly the center of the header 41 in its length direction. The refrigerant pipes 45 are divided accordingly into a first group and a second group. The refrigerant is supplied to the first section of the first header 41. The refrigerant is distributed from the first section among the refrigerant pipes 45 which belong to the first group. The refrigerant flows into the second header 42 through the first group to merge together. The refrigerant is distributed from the second header 42 among the refrigerant pipes 45 which belong to the second group, again. The refrigerant flows into the second section of the first header 41 through the second group. As above, in the first heat exchange part 48, a passage through which the refrigerant flows in a U-shaped manner is formed.

A joint (not shown) as a refrigerant outlet is provided at an end part of the third header 43. The inside of the third header 43 is divided between a first section and a second section with a partition plate (not shown) provided at nearly the center of the header 41 in its length direction. The refrigerant pipes 45 are divided accordingly into a first group and a second group. The first section of the third header 43 is adjacent to the second section of the first header 41. The first section of the third header 43 and the second section of the first header 41 communicate with each other.

The refrigerant flows from the second section of the first header 41 into the first section of the third header 43. The refrigerant is distributed from the first section among the refrigerant pipes 45 which belong to the first group. The refrigerant flows into the forth header 44 through the first group to merge together. The refrigerant is distributed from the fourth header 44 among the refrigerant pipes 45 which belong to the second group, again. The refrigerant flows into the second section of the third header 43 through the second group. As above, in the second heat exchange part 49, a passage through which the refrigerant flows in a U-shaped manner is formed. The refrigerant in the second section of the third header 43 flows out through the refrigerant outlet to flow toward the compressor.

Specific configuration of the refrigerant pipe 45 and so forth will be described. FIG. 3 illustrates a cold storage container 47 with its thickness omitted, and cold storage materials 50 a, 50 b which are hatched. The refrigerant pipe 45 is a porous pipe having refrigerant passages 45 a in which the refrigerant flows. The refrigerant pipe 45 is also referred to as a flat tube. This porous pipe can be obtained by an extrusion manufacturing process. The refrigerant passages 45 a extend along a longitudinal direction of the refrigerant pipe 45, and open at both ends of the refrigerant pipe 45. The refrigerant pipes 45 are arranged in a row. In each row, the refrigerant pipes 45 are arranged such that their principal planes are opposed to each other. The refrigerant pipes 45 define an air passage 460 for heat exchange with air and an accommodating part 461 for accommodating the cold storage container 47 which is described later, between the two refrigerant pipes 45 adjacent to each other.

The evaporator 40 includes a fin 46 for increasing a contact area with the air supplied to the vehicle interior. The fin 46 is provided by corrugate type fins 46. The fin 46 is disposed in the air passage 460 defined between the two adjacent refrigerant pipes 45. The fin 46 is thermally bonded to its two adjacent refrigerant pipes 45. The fin 46 is joined to its two adjacent refrigerant pipes 45 by a jointing material which is excellent in heat transfer. Brazing filler metal can be used for the jointing material. The fin 46 has such a shape that a metal plate such as a thin aluminium is bent in a corrugated manner, and includes the air passage 460 which is referred to as a louver.

The cold storage container 47 will be described below. The evaporator 40 further includes the cold storage containers 47. The cold storage container 47 has a flat cylindrical shape. The cold storage container 47 is closed by crushing the cylinder in its thickness direction at both ends of the container 47 in its longitudinal direction, so that a space for accommodating the cold storage material 50 a, 50 b is formed in the container 47. The cold storage container 47 includes a broad principal plane on both its surfaces. Two main walls which provide these two principal planes are arranged respectively parallel to the refrigerant pipe 45. The container 47 is arranged such that the refrigerant pipe 45 is in contact with at least one surface, in the present embodiment, with both the surfaces of the cold storage container 47.

In the cold storage container 47, more than one, in the present embodiment, two cold storage cases 60 are arranged between the two adjacent refrigerant pipes 45. The cold storage cases 60 are arranged along a flow direction of drawn air. In other words, the cold storage cases 60 are arranged such that the cold storage cases 60 are different between on an upstream side and on a downstream side in a flow direction of air. The cold storage cases 60 respectively accommodate the cold storage materials 50 a, 50 b which are independent and have different melting points.

As illustrated in FIG. 4, for each of the cold storage cases 60, there is provided one or more sealing port 61, through which the cold storage material 50 a, 50 b is sealed. The sealing port 61 is provided at the outer periphery of the cold storage case 60 on an upstream side (windward side) or on a downstream side (leeward side) in a flow direction of air. When the cold storage case 60 is not specified, it is hereinafter referred to as the cold storage container 47.

The cold storage container 47 is thermally bonded to the two refrigerant pipes 45 arranged on both its sides. The cold storage container 47 is joined to its two adjacent refrigerant pipes 45 by a jointing material which is excellent in heat transfer. A resin material such as brazing filler metal or adhesive can be used for the jointing material. The cold storage container 47 is brazed to the refrigerant pipes 45. A large amount of brazing filler metal is arranged between the cold storage container 47 and the refrigerant pipe 45 for connecting them together by a large cross-sectional area. This brazing filler metal can be provided by disposing foil of brazing filler metal between the cold storage container 47 and the refrigerant pipe 45. As a result, the cold storage container 47 shows good heat conduction between the cold storage container 47 and the refrigerant pipe 45.

Thickness of each cold storage container 47 is approximately the same as thickness of the air passage 460. Accordingly, the thickness of the cold storage container 47 is approximately the same as thickness of the fin 46. The fin 46 and the cold storage container 47 can be switched. As a result, an arrangement pattern of more than one fin 46 and more than one cold storage container 47 can be set with a high degree of freedom.

The thickness of the cold storage container 47 is obviously larger than thickness of the refrigerant pipe 45. This configuration is effective for accommodating the large amount of the cold storage materials 50 a, 50 b. The lengths of the cold storage containers 47 are the same as each other. The length of arrangement of the two cold storage cases 60 is approximately the same as that of the fin 46. Accordingly, the cold storage container 47 occupies the almost entire part of the accommodating part 461 defined between its two adjacent refrigerant pipes 45 in a longitudinal direction of the accommodating part 461. Thus, the arranged two cold storage cases 60 have the same area in contact with the refrigerant pipe 45 as each other. In other words, the arranged two cold storage cases 60 have the same area for exchanging heat with the refrigerant pipe 45 as each other. The clearances between the cold storage container 47 and the headers 41 to 44 can be filled with a cut piece of the fin 46 or a filling material such as resin.

The refrigerant pipes 45 are arranged nearly at even intervals. The clearances are formed between these refrigerant pipes 45. In these clearances, more than one fin 46 and more than one cold storage container 47 are arranged with predetermined regularity. A part of the clearances is the air passage 460. The rest of the clearances is the accommodating part 461 of the cold storage container 47. For example, 10% to 50% of total intervals formed between the refrigerant pipes 45 is the accommodating part 461. The cold storage container 47 is arranged in the accommodating part 461.

The cold storage containers 47 are arranged generally in an evenly dispersed manner throughout the entire evaporator 40. The two refrigerant pipes 45 located on both sides of the cold storage container 47 define the air passage 460 for heat exchange with the air on the opposite side from the cold storage container 47. In a different perspective, the two refrigerant pipes 45 are arranged between the two fins 46, and furthermore, one cold storage container 47 including the two cold storage cases 60 which are paired with each other is disposed between these two refrigerant pipes 45.

The cold storage container 47 is made of metal such as aluminium or aluminum alloy. For example, a material containing metal whose ionization tendency is lower than hydrogen as its chief material or component is used for the material of the cold storage container 47 other than aluminium.

The cold storage materials 50 a, 50 b will be described below. The cold storage materials 50 a, 50 b are materials that exchange heat with the refrigerant flowing through the refrigerant passage 45 a to retain the amount of heat from the refrigerant. The cold storage materials 50 a, 50 b retain the heat from the refrigerant by solidifying it, and release the retained heat to the outside by melting it. The cold storage material 50 a having a high melting point is disposed on an upstream side of the cold storage material 50 b having a low melting point in a flow direction of air. Accordingly, in FIG. 3, the cold storage material 50 a in the upper cold storage case 60 has a higher melting point than the cold storage material 50 b in the lower cold storage case 60. An air thermal load on a windward side of the evaporator 40 tends to be higher, so that the cold storage material 50 a having a high melting point which is easily solidified despite high temperature is disposed on a windward side and the cold storage material 50 b having a low melting point is disposed on a leeward side.

The melting point of the high melting point cold storage material 50 a which is a cold storage material having a high melting point may be equal to or higher than a cooling temperature zone at the time of refrigerated air conditioning, i.e., may be 5 degrees Celsius to 25 degrees Celsius. The melting point of the low melting point cold storage material 50 b which is a cold storage material having a low melting point may be 0 degrees Celsius to 15 degrees Celsius. When the melting point of the high melting point cold storage material 50 a ranges from 5 degrees Celsius to 15 degrees Celsius, the melting point of the low melting point cold storage material 50 b is 0 degrees Celsius or higher, and is lower than the melting point of the high melting point cold storage material 50 a. Furthermore, the melting point of the high melting point cold storage material 50 a is not higher than a thermal sensing permissible value (=15 to 17° C.) of blown-out air, and thus, may be 15° C. or lower. The melting point of the low melting point cold storage material 50 b may range from 0° C. to 10° C. so that the cold storage material 50 b can be solidified and melted even at low temperature such as during winter season. The necessary amount of heat of the two cold storage materials 50 a, 50 b may be approximately 200 kJ/kg or larger in view of the volume of the cold storage container 47. Accordingly, the cold storage capacity necessary at the time of an idling stop can be ensured.

Generally, an organic material has a small heat conductivity, and greatly supercools except paraffin series. In chemical heat storage, it is chemical stability, a poisonous substance, corrosiveness, and a reaction facilitator (pressure holding and agitation necessary). Accordingly, in the present embodiment, two types of paraffin are used as the cold storage materials 50 a, 50 b.

The paraffin used for the high melting point cold storage material 50 a may have the carbon number of 16 or 15. The paraffin used for the low melting point cold storage material 50 b may have the carbon number of 15 or 14. When the carbon number of the paraffin of the high melting point cold storage material 50 a is 16, the carbon number of the low melting point cold storage material 50 b may be 15 or 14. When the carbon number of the paraffin of the high melting point cold storage material 50 a is 15, the carbon number of the paraffin of the low melting point cold storage material 50 b may be 14. Accordingly, even the same paraffin can have different melting points from each other. In addition, a cold storage material having hydrate as its main component may be employed.

Operation of this embodiment will be described below. When a request for air conditioning, for example, a request for refrigerated air conditioning is made by an occupant, the compressor is driven by the power source. The compressor draws in the refrigerant from the evaporator 40, compresses the refrigerant, and discharges the refrigerant. The heat of the refrigerant discharged from the compressor is released at the radiator. The refrigerant which has flowed out of the radiator is decompressed by the decompressor to be supplied to the evaporator 40. The refrigerant evaporates at the evaporator 40 to cool the cold storage container 47, and cools its surrounding air via the fin 46. When the vehicle makes a temporary stop, the power source stops to reduce energy consumption and the compressor is thus stopped. Then, the refrigerant of the evaporator 40 gradually loses its cooling capacity. In this process, the cold storage materials 50 a, 50 b radiationally cool gradually to cool the air. In this case, the heat of air is conducted to the cold storage materials 50 a, 50 b via the fin 46, the refrigerant pipe 45, and the cold storage container 47. As a result, even though the refrigeration cycle system is temporarily stopped, the air can be cooled by the cold storage materials 50 a, 50 b. After a while, when the vehicle begins to travel again, the power source drives the compressor again. Thus, the refrigeration cycle system cools the cold storage materials 50 a, 50 b again and the cold storage materials 50 a, 50 b store the cold.

To describe a more specific operation with reference to FIG. 5, when the air-conditioner is in operation under the normal control at the time of a high load during summer season or at in-between stages, the refrigerant temperature is lower than the melting points of both the high melting point cold storage material 50 a (A in FIG. 5) and the low melting point cold storage material 50 b (B in FIG. 5), so that the cold storage materials 50 a, 50 b are solidified to store the cold air. During an idling stop, the solidified col storage materials release the stored cold air into the air, being melted to limit a temperature rise of blown-out air, thereby extending an idle stop time.

When a fuel saving mode is in use, the refrigerant temperature is higher than at the time of the high load. In such a case, when the air-conditioner is in operation, only the high melting point cold storage material 50 a is solidified and can accumulate the cold air. During an idling stop at the time of the fuel saving mode, the high melting point cold storage material 50 a releases the accumulated cold air into the air, being melted to limit a temperature rise of blown-out air, thereby extending an idle stop time.

As described above, in the evaporator 40 of the present embodiment, as the cold storage materials 50 a, 50 b having different melting points, in the present embodiment, the two cold storage materials 50 a, 50 b are divided from each other and accommodated respectively in the cold storage container 47. The cold storage material 50 a having a high melting point is disposed on an upstream side of the cold storage material 50 b having a low melting point in a flow direction of air. Accordingly, when the temperature of the refrigerant is, for example, equal to or lower than, the melting point of the high melting point cold storage material 50 a, and is equal to or higher than the melting point of the low melting point cold storage material 50 b, only the high melting point cold storage material 50 a is solidified. As a result, even though the refrigerant temperature is high, the cold storage can be carried out. When the refrigerant temperature becomes further low, all the cold storage materials 50 a, 50 b are solidified. Thus, the cold can be stored in stages in accordance with the refrigerant temperature. Therefore, a cold storage function can be maintained in a wider range of air temperature.

The sealing port 61 is provided at the outer periphery of the cold storage case 60 on an upstream side or on a downstream side in a flow direction of air. Accordingly, the sealing port 61 is not provided in the air passage 460, so that the sealing port 61 can be prevented from becoming a draft resistance.

Second Embodiment

A second embodiment will be described in reference to FIGS. 6 and 7. The present embodiment is characterized in that cold storage cases 60A are arranged to be in contact with each other. Because of such a configuration in which the cold storage cases 60A are in contact, the space can be used more effectively. Accordingly, the amount of cold storage materials 50 a, 50 b, with which a cold storage container 47 can be filled, can be made large. Operation and effects of the other configuration are similar to the above-described first embodiment.

Third Embodiment

A third embodiment will be described in reference to FIG. 8. The present embodiment is characterized in that the inside of a cold storage container 47C is divided by a partition 70, and that cold storage materials 50 a, 50 b having different melting points are accommodated respectively in the divided spaces. One sealing port 61, through which the cold storage material 50 a, 50 b is sealed, is provided for this cold storage container 47C. Accordingly, two types of the cold storage materials 50 a, 50 b are sealed through the one sealing port 61. As a result, the configuration is simplified, and is easily handled as the cold storage container 47C. The sealing port 61 is provided at the outer periphery of the cold storage container 47C on an upstream side or on a downstream side in a flow direction of air, and is provided on a leeward side in the present embodiment. Because of such a configuration, the space can be used more effectively. Accordingly, the amount of the cold storage materials 50 a, 50 b, with which the cold storage container 47C can be filled, can be made large. Operation and effects of the other configuration are similar to the above-described first embodiment.

Fourth Embodiment

A fourth embodiment will be described in reference to FIG. 9. The present embodiment is characterized in that cold storage cases 60D are arranged to be away from each other and that both two sealing ports 61 are on the same side. As a result of such a configuration as well, operation and effects similar to the above first embodiment can be achieved.

Fifth Embodiment

A fifth embodiment will be described in reference to FIG. 10. The present embodiment is characterized in that cold storage cases 60E are formed integrally to be in contact with each other and that both two sealing ports 61 are on the same side. As a result of such a configuration as well, operation and effects similar to the above second embodiment can be achieved.

Sixth Embodiment

A sixth embodiment will be described in reference to FIG. 11. The present embodiment is characterized in that cold storage cases 60F are formed integrally to be in contact with each other and that both two sealing ports 61 are on the same side. Furthermore, one of the sealing ports 61 is configured as a pipe 61F. As a result of such a configuration as well, operation and effects similar to the above second embodiment can be achieved.

Seventh Embodiment

A seventh embodiment will be described in reference to FIG. 12. The present embodiment is characterized in that cold storage cases 60G are arranged on one side of a refrigerant passage 45 a. The configuration illustrated in FIG. 12 is of a “drawn cup type”. As a result of the arrangement on one side of a refrigerant passage 45 a, the space can be conserved as a whole. As a result of such a configuration as well, operation and effects similar to the above first embodiment can be achieved.

Eighth Embodiment

An eighth embodiment will be described in reference to FIGS. 13 and 14. The present embodiment is also characterized in that cold storage cases 60H, 60I are arranged on one side of a refrigerant passage 45 a similar to the above seventh embodiment. The two cold storage cases 60H, 601 extend along a flow direction of air and are arranged along the flow direction of air. FIG. 13 illustrates that the cold storage cases 60H are arranged at intervals in the flow direction of air. FIG. 14 illustrates that the cold storage cases 601 are arranged to be in contact with each other in the flow direction of air. In this manner, by arranging the cold storage cases 60H, 601 only on one side of the refrigerant passage 45 a, the space can be conserved as a whole. Moreover, operation and effects similar to the above first embodiment can be achieved.

Ninth Embodiment

A ninth embodiment will be described in reference to FIGS. 15 to 17. As illustrated in FIGS. 15 and 16, the present embodiment is characterized in that one type of a cold storage material 50 is accommodated in each cold storage container 47J. In addition, the present embodiment is characterized in that a high melting point cold storage material 50 a is accommodated in one of the adjacent cold storage containers 47J, and a low melting point cold storage material 50 b is accommodated in the other one of the adjacent cold storage containers 47J. The present embodiment can be applied to a case where the cooling capacity of an evaporator 40J is sufficiently high.

Accordingly, the cold storage container 47J accommodating the high melting point cold storage material 50 a, and the cold storage container 47J accommodating the low melting point cold storage material 50 b are arranged alternately between refrigerant pipes 45. FIGS. 15 and 16 illustrate the cold storage container 47J in which the high melting point cold storage material 50 a is accommodated.

To describe a specific operation with reference to FIG. 17, when the air-conditioner is in operation under the normal control at the time of a high load during summer season or at in-between stages, the refrigerant temperature is lower than the melting points of both the high melting point cold storage material 50 a (A in FIG. 17) and the low melting point cold storage material 50 b (B in FIG. 17), so that the cold storage materials 50 a, 50 b are solidified to store the cold air. During an idling stop, the solidified cold storage materials release the stored cold air into the air, being melted to limit a temperature rise of blown-out air, thereby extending an idle stop time.

When a fuel saving mode is in use, the refrigerant temperature is higher than at the time of the high load. In such a case, when the air-conditioner is in operation, only the high melting point cold storage material 50 a is solidified and can accumulate the cold air. During an idling stop at the time of the fuel saving mode, the high melting point cold storage material 50 a releases the accumulated cold air into the air, being melted to limit a temperature rise of blown-out air, thereby extending an idle stop time.

In the above-described first embodiment, if the temperature on the windward side of the evaporator 40 is high and the low melting point cold storage material 50 b is not solidified, the high melting point cold storage material 50 a can be disposed on the windward side, and the low melting point cold storage material 50 b can be disposed on the leeward side. However, if the cooling capacity of the evaporator 40J is sufficiently high and the temperature of the evaporator 40J decreases almost evenly in a flow direction of air as in the present embodiment, the high melting point cold storage material 50 a does not need to be disposed only on the windward side. Thus, by disposing the single cold storage container 47J along the flow direction of air as in the present embodiment, operation and effects similar to the above first embodiment can be achieved.

In the present embodiment, the cold storage containers 47J having different melting points are arranged alternately (high melting point—low melting point—high melting point . . . ). However, the present disclosure is not limited to this alternate arrangement. For example, instead of the one-by-one alternate arrangement, the cold storage containers 47J may be arranged alternately two by two (high melting point—high melting point—low melting point—low melting point—high melting point—high melting point . . . ), or may be arranged alternately three by three. In other words, at least a part of the cold storage material 50 a of the cold storage materials 50 a, 50 b accommodated in the cold storage containers 47J may have a different melting point from the cold storage material 50 b accommodated in another cold storage container. Accordingly, the cold storage container 47J accommodating the high melting point cold storage material 50 a, and the cold storage container 47J accommodating the low melting point cold storage material 50 b do not need to be the same in number. Depending on a temperature distribution of the refrigerant flowing through the evaporator 40J, the melting point and volume of the cold storage material 50 accommodated in each cold storage container 47J may be appropriately selected.

The embodiments have been described above. The present disclosure is not by any means limited to the above embodiments, and can be embodied in various modifications without departing from the scope of the present disclosure.

The structures of the above-described embodiments are only exemplifications, and the scope of the present disclosure is not limited to these descriptions. The scope of the present disclosure is recited in the scope of claims, and includes all the modifications within a meaning and a range equivalent to the recital of the scope of claims.

In the above first and ninth embodiments, there are two types of the cold storage materials 50 a, 50 b. However, they do not need to be of two types, and may be of three or more types. Accordingly, the cold can be stored further in stages, and the present disclosure can be applied to a wider air-conditioning temperature range.

The refrigerant pipe 45 can be provided by a porous extrusion pipe or a pipe that is obtained by cylindrically bending a plate material including dimples. Furthermore, the fin can be eliminated. Such a heat exchanger is also referred to as a finless-type heat exchanger. The heat exchange with air may be promoted by providing, for example, a ridge extending out of the refrigerant pipe instead of the fin.

The cold storage case 60 does not need to be disposed at the outer periphery of the refrigerant pipe 45, and the cold storage case may be disposed in the refrigerant passage. There may be one cold storage case 60. For example, the heat exchanger may be disposed transversely, and a cold storage material having a high melting point and a high specific gravity, and a cold storage material having a low melting point and a low specific gravity may be arranged to be sealed in one container. Accordingly, the cold storage material having a high melting point can exist on an upstream side in a flow direction of air without preparing more than one cold storage case for separation.

In the above-described first embodiment, there are more than one type of cold storage materials. However, a mixture of the cold storage materials may be used.

The present disclosure can be applied to an evaporator having various flow paths. For example, the present disclosure may be applied to an evaporator such as one direction type evaporator or a front-rear U-turn type evaporator instead of the right-left U-turn type as in the first embodiment.

Furthermore, the present disclosure may be applied to a refrigeration cycle system for refrigeration, for heating, or for hot water supply, for example. Moreover, the present disclosure may be applied to a refrigeration cycle system including an ejector.

Additionally, an inner fin may be provided in the cold storage container 47. In the case of such a configuration, an opening, from which a top part of the inner fin is exposed, may be provided at an outer shell of the container 47, and the top part of the inner fin may be joined directly to the refrigerant pipe.

While the present disclosure has been described with reference to embodiments thereof, it is to be understood that the disclosure is not limited to the embodiments and constructions. The present disclosure is intended to cover various modification and equivalent arrangements. In addition, while the various combinations and configurations, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the present disclosure. 

What is claimed is:
 1. A cold storage heat exchanger for exchanging heat with air flowing therearound, the cold storage heat exchanger comprising: a refrigerant passages in which refrigerant flows; and a cold storage container that accommodates therein a plurality of cold storage materials which exchange heat with the refrigerant flowing through the refrigerant passage and which retain an amount of heat from the refrigerant, wherein the plurality of cold storage materials having different melting points are accommodated in the cold storage container.
 2. The cold storage heat exchanger according to claim 1, wherein: the plurality of cold storage materials include a cold storage material having a high melting point, and a cold storage material having a low melting point; and the cold storage material having the high melting point is provided on an upstream side of the cold storage material having the low melting point in a flow direction of air.
 3. The cold storage heat exchanger according to claim 1, wherein: the cold storage container is one of a plurality of cold storage containers; one type of cold storage material of the plurality of cold storage materials is accommodated in each of the plurality of cold storage containers; and a cold storage material of the plurality of cold storage materials that is accommodated in at least a part of the plurality of cold storage containers has a different melting point from that of a cold storage material of the plurality of cold storage materials that is accommodated in another one of the plurality of cold storage containers.
 4. The cold storage heat exchanger according to claim 1, wherein: the plurality of cold storage materials are two cold storage materials having different melting points; a melting point of a cold storage material of the two cold storage materials that has a high melting point ranges from 5° C. to 25° C.; a melting point of a cold storage material of the two cold storage materials that has a low melting point ranges from 0° C. to 15° C.; and when the melting point of the cold storage material having the high melting point ranges from 5° C. to 15° C., the melting point of the cold storage material having the low melting point is 0° C. or higher, and is lower than the melting point of the cold storage material having the high melting point.
 5. The cold storage heat exchanger according to claim 1, further comprising a refrigerant pipe that is disposed on a least one surface of the cold storage container, wherein the refrigerant pipe includes the refrigerant passages.
 6. The cold storage heat exchanger according to claim 2, wherein: the cold storage container includes a plurality of cases independent of each other; the plurality of cases are arranged to be different between on an upstream side and on a downstream side in the flow direction of air; and each of the plurality of cold storage materials having different melting points is accommodated in a corresponding one of the plurality of cases.
 7. The cold storage heat exchanger according to claim 6, wherein each of the plurality of cases includes at least one sealing port through which its corresponding one of the plurality of cold storage materials is sealed.
 8. The cold storage heat exchanger according to claim 1, further comprising a partition that divides inside of the cold storage container, wherein each of the plurality of cold storage materials having different melting points is accommodated in a corresponding one of a plurality of spaces divided by the partition.
 9. The cold storage heat exchanger according to claim 8, wherein the cold storage container includes at least one sealing port through which the plurality of cold storage materials are sealed.
 10. The cold storage heat exchanger according to claim 7, wherein the at least one sealing port is provided at an outer periphery of the cold storage container or its corresponding one of the plurality of cases on an upstream side or on a downstream side in the flow direction of air.
 11. The cold storage heat exchanger according to claim 1, wherein the plurality of cold storage materials include paraffin or hydrate as their main component.
 12. The cold storage heat exchanger according to claim 4, wherein: a carbon number of paraffin used for the cold storage material having the high melting point is 16 or 15; a carbon number of paraffin used for the cold storage material having the low melting point is 15 or 14; when the carbon number of paraffin for the cold storage material having the high melting point is 16, the carbon number of paraffin for the cold storage material having the low melting point is 15 or 14; and when the carbon number of paraffin for the cold storage material having the high melting point is 15, the carbon number of paraffin for the cold storage material having the low melting point is
 14. 13. The cold storage heat exchanger according to claim 9, wherein the at least one sealing port is provided at an outer periphery of the cold storage container or its corresponding one of the plurality of cases on an upstream side or on a downstream side in the flow direction of air. 